"""
stringa = input()
stringb = input()
"""
str_a = "a,o,c,d,f"
str_b = "pmcdfa"

long = len(str_a)
count = sum(range(0, long + 1))

i = 0
lst = []
while long + 1 > 0:
    for i in range(1, long + 1):
        new_s = str_a[0:i]
        lst.append(new_s)
    long -= 1

# print(sum(range(1:long)))
